I just want to point out that you are wrong according to SANS, and they are cooler than you!
http://www.sans.org/reading-room/whitepapers/win2k/basic-security-issues-active-directory-191
(page 6)
"If your organization has a presence on the Internet, the name of your forest root domain
should be registered. An example would be the SANS Institute, which would use sans.com as a DNS namespace for the Internet, and sans.com would be the namespace for their Active Directory forest root domain"